The present disclosure relates to an aluminum alloy and a method of producing the same, and more particularly, to an aluminum alloy including magnesium and silicon as alloy elements and a method of producing the same.
An aluminum-magnesium-silicon (Mg—Al—Si) alloy in which magnesium (Mg) and silicon (Si) are added to aluminum (Al) corresponds to the 6000 series on classifications derived from the US aluminum association, and is used as a wrought material having excellent corrosion resistance and formability. A 6063 alloy that is a representative Mg—Al—Si alloy has excellent extrudability and surface treatment characteristic and thus is much used as a construction material, and a 6061 alloy in which more magnesium and silicon are added than the 6063 alloy has a higher mechanical strength than the 6063 alloy, and thus is used in a crane, a vehicle bump, etc. requiring lightweight and high strength.
In such an Mg—Al—Si alloy, an intermetallic compound of Mg2Si is precipitated and distributed in an Al matrix by heat treatment and the strength is increased due to the Mg2Si precipitate phase.
The phase diagram of Al—Mg2Si exhibits a solid solubility of Mg2Si to Al that approaches 1.85% at 595° C. but sharply decreases as the temperature drops and has a value close to about zero (0) at room temperature. Therefore, when the temperature drops in a state that Mg2Si is solid-solutioned, a large amount of Mg2Si is precipitated in a matrix due to a difference in solid solubility according to the temperature, and mechanical properties of aluminum alloys are improved by such Mg2Si. In detail, an alloy that is produced by adding magnesium and silicon to aluminum is solution-treated at 515-550° C., then cooled with water, and then aged at 170-180° C. to precipitate Mg2Si. Thus, in the case of a related art Mg—Al—Si alloy, a series of heat treatment processes should be necessarily performed in order to precipitate Mg2Si.